Which should I trust?

theron12

Which is more accurate as far as calories burned? Treadmill vs FitBit

susanofarrell

The lowest one (if you want trust)

MontyMuttland

Neither.
Normally I'd say your activity monitor should give a more accurate measurement, but your Fitbit is clearly telling you a bunch of gaga.
It can happen that you get a bad one when you buy an activity monitor. I've no specific experience with Fitbits, though I've seen complaints elsewhere on forum posts about poor accuracy.
I had two Garmin Forerunner 35s which gave completely different results for the same activity, the first one giving way too much calorie burn the same as your Fitbit is doing.
If you have the chance to do it, get that one sent back for a replacement.
Typically the gym equipment calorie burn measurements will be generous, so in this case even though it's showing a lower result for your exercise than the Fitbit, this result is probably higher than your actual burn as well.
If you're trying to work out how many calories you can give yourself back to eat from the exercise, best advice is to go for half the amount shown on the device which showed the lowest burn.
The real value is probably in the region of 150 Calories. Hopefully if you get your Fitbit replaced, the new one will show results closer to that.

JeromeBarry1

If the cardio machine does not know your weight and does not monitor your heart rate (I do not know if this applies to that machine) it uses a one-size-fits-all calculation which assumes that every user is 150 lb. Rather, many machines do. There may be some which assume a different user weight. Larger people burn more, smaller people burn less. If you're doing cardio, your fitbit is likely to have a more accurate read on you. That 2x difference, though, would leave me doubting which direction the Sun rises.

beatyfamily1

I've noticed my Fitbit gives me a little bit lower than what my treadmill says, but my Fitbit doesn't have the heart rate monitor. My Fitbit is usually about 80 calories less than what my treadmill says. Either way, I would count them as extra calories burned. I wouldn't try to eat those calories back unless you are doing a lot.

Psychgrrl

A 10 calorie per minute burn is an extremely intense level of exercise. One most of us can't sustain for an entire workout. So, your Fitbit giving you 450 for a 30 minute workout with an average heart rate of 130 doesn't really jibe.

Is your Fitbit new? Maybe it needs time to calibrate. You can call Fitbit support--I hear they have great customer service--and ask them. Maybe you have a funky one.

Trying plugging your stats and exercise into one of the online calculators like sparkpeople.com to get another perspective.

Heather4448

My Fitbit is dead-on. It's amazing, really. I know this isn't the case for everyone, which is why most MFP peeps tell you to eat back 50-75% of your exercise calories.

spiriteagle99

If you were walking 3 mph for 30 minutes, it isn't that hard to calculate burn. The machine doesn't know how much you weigh, which makes a big difference. I don't know why the fitbit was so high, but it's obviously off, unless you were doing your 1.5 miles at an incline of 10.

I use MFP's numbers for walking and running, which are a bit low for me because they don't include incline. Still, it's close enough. I get about 80 calories per mile when running.

Chadxx

In this case, the treadmill and for those not familiar with it, that one does ask for your weight.